Interest-computing machine



S. P. THOMPSON.

INTEREST COMPUTING MACHINE.

APPLICATION FILED DEC. I4, 1917.

PilItlItPd July 22, 1919.

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INTEREST COMPUTING MACHINE.

APPLICATION FILED DEC-14.1917.

Patented July 22, 1919.

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STANLEY P.'.THOMPSON, OF SEATTLE, WASHINGTON.

INTEREST-COMPUTING MACHINE.

To all whom it may concern:

- Be it known that I, STANLEY P. THoMr-' .soN, a citizen of the UnitedStates, and resident of the city of Seattle, county of King, and Stateof Washington, have inventedcertain new and-useful Improvements in Interest-ComputingMachines, of which the following is a specification.

My invention .-relates to; computing devices and consists of anapparatus which may be employed for computing interest at various ratesand for various times.

The. object of my invention is to provide a device such that theinterest due on any amount may be determined thereby through theaddition only of sums which will be indicated by the operation thereof,it being possible to in this way find the interest on any amount for anytime, at any rate.

My invention=comprises the novel parts and combinations thereof whichwill be hereinafter described and then particularly pointed out in theclaims.

In the accompanying drawings I shown my device embodied in "the type ofgonstruction which is now most preferred y me.

Figure 1 is a face view of one of the indicating faces of my device.

Fig. 2 is a. cross section of the same show-- ing the operating partscontained therein.

Fig. 3 is an end view of the device showing the end containing the knobsby which it is operated.

Fig. at is a vertical longitudinal section on a larger scale through oneend of the companion pair of rollers.

Fig. 5 is .a detail showing the end of one of the roller shafts uponwhich the device for limiting its turning is 'moun Fig. 6 is a crosssection through the nut which is mounted upon, this end of the shaft. i

Fig. 'Z-is a cross section of the shaft showing the manner of mountingthe stop therein.

Fig. 8 shows a. short section of the web and the figures thereon.

Specification of Letters Patent.

Application filed December 14, 1917. Serial No.

Patented July 22, 1919.

the. interest on the principal at .the given rate for a certain lengthof time, which length of time is indicated by figures 13 which areplaced upona fixed member which alines with the columns of the web andwhich represents the number of days upon which the interest runs. r

In Fi 8 I have shown a short section of one ace of a web, This showseleven columns, each of which has its figures trans versely alined so asto form lines. As'

stated, the first column represents the prin- -cipal, the second, whichmight be omitted have In carrying out my invention I provide a certainnumber of webs 1, these being made of paper, or other like material, andhaving printed thereon certain columns of figures, one of which, as theleft hand one.

which is lettered 10, represents certain amounts of principal upon whichinterest is to be determined. Another, 11, adJacent thereto, representsthe interest rate and if a single rate of interest only was shown on theface of the web, represents the rate of interest, and the other columnsthe amount of interest for its principal amount for a certain number ofdays.

As shown in Fig. 8, and as I contemplate showing it in most cases, theinterest for two different rates are shown upon the same side of theweb, these rates alternating. That is, for each principal amount theinterest for the two rates are placed in alternate and successive lines,that is, for exeach of the series of columns 12 represents ample asshown in Fig. 8, the interwt is' 7 shown on one face for 5% and 7%, oneline being for 5% and the next for 7%, and both lines being associatedwith the same principal amount.

I contemplate having these webs printed upon both sides, the mechanismbeing so constructed that one side is exposed at one side of the casingin which the mechanism is mounted, and the other side of the web isexposed at the other side of the same casing. It is thus possible toshow four different rates of interest upon the same web. I have chosenfor the present case to show the interest at 5%, 6%, 7%, and 8%.

The casing 2 has a window opening 20 at *two opposite sides centrallyplaced in the are placed rollers to which the ends of the web aresecured. These rollers are arranged in pairs, the rollers 3'-having oneend of a web secured thereto and the rollers 30 having the other end ofthe same web secured thereto. The companion rollers to which the ends ofthe same web are secured, are arranged one above the other and areprovided with gear wheels 31 connecting them so that I they arecompelled to turn together.

In connection with each pair of rollers I also provide two small idlerrollers4, these being mounted close to the inner faces of the glass 21,at opposite sides of the casing 2. The web leading from a roller 3 firstpasses over the idler roller 4 which is at that' side of the casing,thence back into contact with the opposite side of the roller 3, aboutone side of the roller'30, thence to the idler roller 4 at the otherside of the casing, back to the roller 30 to which this end thereof issecured. In this manner the two sides of the web are exposed, one at oneside of the casing and the otherat the other side. I

The inner surface ofthe glass 21 is provided with a surface which isopaque except for certain slots through which one line of the figures ofthe web 1 may be seen. This coating 22 is preferably made of paper andhas the slots 23 cut therein of a width to render a line on the webvisible. This paper also has the figures 13 printed thereon, saidfigures indicating the number of days for which the interest is to becalculated, the number of days corresponding with the interest ratesshown in the corresponding column of the web.

Figures 13, which indicate the time element, are placed upon the paper22 in such position as to indicate the point where the decimal point isto be placed in the interest amount shown on the web. The fi ures 13, asshown in the drawings, are all in multiples of one hundred. Where theinterest is for an exact number of hundreds of days, the decimal pointis to be placed in the figures 14, the same being the columns whereinthe amount of interest is shown, directly under or in alinement with theright end of the figures representing the time. If the time is only tendays then it is evident that the decimal point will be shifted one pointto the left and for one day it will be shifted one more point to theleft. Contrariwise, if

the time should be one thousand days, the decimal point would be shiftedone point to the right. In this way it is possible to determine theamount of the interest for any number of days.

Taking the device with the setting shown in Fig. 1, the principal amountas shown by the uppermost line is $610,000; the principal amount, asshown by the second line, is $4800; while the principal amount as shownby the lowermost line is 9515. Therefore, if

we use all of these three lines for our purpose, the total principalamount indicated by the columns showing the amount of principal will be$614,815.00. To obtain the interest on this amount for one hundred dayswe will, therefore, add the indications shown in the three lines. Theupper line would give us $11,861.11, this being the interest on $610,000at 7% for one hundred days.

The second line would give us $93.33, as the interest on $4800 at 7% forone hundred days, while the third line would give us $.29 as theinterest on $15.00 at 7 "a for one hundred days. The sum of theseamounts which is $11,954.73, is obtained by adding the interest amountsshown in the three lines for the time of one hundred days, which givesus the interest on the total amount.

The number of lines placed upon the web are suflicicnt so that theinterest may be obtained on any amount from $1.00 to $999,999.00, at anyrate for which the interest has been figured. In the device as shown,this would be for 5%, 6%, 7% and 8%. If interest at other rates isdesired, this may be obtained by multiplication or division. Forinstance, at 4% the interest at 8% would be determined and this amountdivided by two.

Likewise, for 39 the interest at 7% would be determined and this-amountdivided by two. In many cases where the amounts are in exact hundreds orthousands, it may be necessary to read only from one or two of thelines.

To prevent over-turning of the rollers 3 and 30, to which the Webs 1 aresecured, I have provided a stop device which is shown in Figs. 5, 6, and7. By this device I provide one of the shafts 32, upon which the rollers3 and 30 are mounted, with athreaded section 33, at one end. Thisthreaded section projects beyond the gear 31 for this roller. Mountedupon this threaded section 33 is a nut 5, which nut should be heldagainst rotation in some manner. The manner of doing this herein shownconsists in providing the nut at -opposite sides with slots 50, in whichare placed the arms 60 forming extensions of a plate 6, which plate isprovided with a hole through which extends a pin 61, which is secured tothe frame. The nut and its attached arm 6, are thus moved lengthwise ofthe shaft 32, as it is actuated by the turning of the shaft.

To secure stoppage of the shaft 32 against rotation without jamming ofthe nut, I employ pins 34: located one at each end of the threadedsection 33, these pins being placed squarely in the hollow betweenthreads, and coiiperating shoulders 51 formed at each side of the nut bycutting away one of the threads. This provides radial stop surfaces onboth shaft and nut, so that there can be no jamming of the nut.

By reason of providing a positive stop in its rotation. This isdesirable by reason of the rolls so that it may yield.

One manner of doing this and that now preferred by me, is shown in Fig.4; The

rolls 3 are herein shown, as hollow, the roll 30 might as well be madesolid, if desired. Within the roll 3 is, however, mounted a torsionalspring 7, which sprin although 7 is connected at one endv with the shaft32,

as is shown at 70, and at its other end is connected with the roll 3.Therefore, the rotativ'e effort between the gear 31 and the roll 3 iscommunicated through the spring 7,. thus permitting a slight turningmovement between the gear and the roll, thus accommodating for thedifferences in diameter in the rolls which is produced by the piling ofone end of the web upon itself upon the roll.

It may be desired to adjust the initial tension of the spring 7. Thismaybe secured in the following manner:

The ends of the shafts 32, which are opposite to. that upon which thegears 31 are secured, project through the end walls of the casing 2 andare preferably provided with knobs or wheels 35 by which they may beconveniently turned. If these knobs be made. removable from the shafts,as may be done by securing them thereon through .the means of a pin, andif then one of these shafts be pushed,inward until the gear 31 securedthereto has been disengaged from the intermeshing gear 31, the gear 31,which is associated with 'the roll in which the spring is contained, maybe turned so as to increase or decrease the initial tension upon thespring 7. In this manner the tension upon the spring 7 may be adjusted.It may be noted that the gears 31 are secured against turning upon theshafts 32.

I prefer to provide the gears 31, especially those which are mountedupon the shaft which is movable in order to adjust the tension of thespring, with an internal flange 36 or equivalent ears, so that when thegear is moved outward in order to dis-- engage it from its companiongear, the flange will not be entirely removed from the tubular roll 3. v

In the device as herein shown I have employed three sets of rolls 3 and30, and three sets of idler rolls 4. This slot should be ofsuch a widthas to show but one line of figures upon the web except possibly at theleft hand end where the principal amounts are shown. This slot may bemade 'of double width at this point in such cases wherein two differentinterest rates are shown on the same face of the web. This permits viewor the principal amount when the web is turned for either of theinterest rates which are shown upon the web. In lieu .of this theprincipal amount may be duplicated upon the web.

For convenience in using this device I prefer to mount it in such mannerthat it maybe bodily turned upon a. pivot axis so as to bring either ofthe two sides which are to be inspected uppermost; A manner of doingthis and the one-which I now prefer to use is shown and consists ofthefollowing.

At one end of the case, being the end at which the knobs 35 aresecuredto the shafts, I provide the end of the casing with a circularflange ring 8. A base 9 is provided with a pair of rollers 90 upon whichthe flange ring 8 rests. To prevent removal of the flange ring'the base9 may have flange sections 91 which project over the flange ring 3. Atthe opposite end-of the casing a single pivot axis 92 may besecured tothe end of the casing, this being.journaled in an upright frame formedby the two bars 93. The two end portions of the base may be connectedbybars 94. For convenience.

the twoparts of the standard may be disengageably connected, as by meansofbolts or screws 95. In this manner the casing may be convenientlyturned so as tobring either side in an uppermost position and also'toadjust it in angular position, as in Fig. 3. This position will in manycases be found desirable and convenient in the use of the device.

What I claim as'my invention is: 1. An interest computing devicecomprising a casing having a plurality of related webs therein, sightopenings formed in the to indicate where the decimal point W1 1 fall indetermining the interest for units, tens, or hundreds of days.

2. In a device-of the character described the combination with a casinghaving a sight opening, of a plurality of indicia carrying webs thereincarrying columns of figures indicative of principal amounts and columnsindicative of interest amountsrelating thereto, figures indicative ofhundreds of days carried by the casing in aline-- ment with the lattercolumns, rollers of con-- siderable size over which said webs travel andby which movement is imparted to the webs and guide rollers of muchsmaller di ameter than the first named rollers arranged in proximity tothe sight openings and c ose together so that a plurality of items oflike nature upon the several webs will be brought into such proximity asto permit them to be conjointly read and added.

3. An interest computing device comprising a casing having a sightopening, a plurality of webs therein means for causing said webs totraverse said sight opening, each of the webs having a column of figuresrepresenti principal amounts, the said columns 0 the several websdiffering in deelmal values, a plurality of columns upon each webrepresenting interest amounts upon the principal amounts carried by theweb, said columns being vertically disposed and the said interestamounts alined horizontally with the principal amounts to which theyrelate and the difi'erent columns of interest amounts difl'ering inrespect to the time for which the interest is figured, and timeindicating figures upon the casing, the columns of interest amounts uponthe several webs alining vertically beneath the time indicating figuresto which they relate whereby they may be added in the usual manner, timeindicating figures having the units of WlllCll they are composed sorelated to the units composing the interest amount ing exposed to viewat one side of the cas- I ing and the other sides of said webs beingexposed to view at the other side of said casing said webs carryingmatter of a nature requiring the amounts upon the several webs to beadded;

5. In a device of the character described the combination with aplurality of webs carrying matter of such nature as to require thecomplemental consideration thereof, a casing in which said webs aremounted, sight openings in the opposite sides of said casin a mountingfor said casing which permits the same to be bodily rotated and guidemeans for said web of such nature that the opposite sides of the severalwebs are exposed to view at the respective sight openings.

Signed at Seattle, Washington, this 8th day of December, 1917.

STANLEY P. THOMPSON.

